Apparatus for Manufacturing a Face Gear

ABSTRACT

A precision grinding apparatus for grinding face gears having a gear table portion controllably driven for rotation about a central axis, and also being movable in a vertical plane along an axis in a controlled manner. The apparatus further includes a case hardened face mounted on the gear table portion. A grinding wheel mounted on the apparatus has controlled driven rotation about a central axis C, and is provided with a grinding surface of predetermined shape. The grinding wheel is movable in a controlled manner toward and away from the gear along a feed axis V, the grinding wheel being movable in a controlled manner in a tangential direction with respect to the gear and orthogonal to the feed axis along a tangential feed axis wherein the motion of the grinding wheel in the C, V and TF axes, and movement of the gear in B and W axes, is controlled by a central control means.

BACKGROUND OF THE INVENTION

The present invention is directed generally to a method and apparatusfor the development of face gears and, more specifically, to a methodand apparatus for the development of face gears suitable for high powertransmission.

The development of face gears for high power transmission is arelatively recent phenomenon. Historically, the transmission of powerthrough a face gear set has been limited to relatively low levelsbecause of two factors: 1) the tooth profile of the mating gears hasbeen generated by shaper cutting; and 2) although an acceptable toothprofile could be generated, the tooth produced by the shaping operationdid not have a hardened surface. The tooth profile produced by theshaping operation required that the resulting face gear set be kept inalmost perfect alignment. In the past, any operation performed on theface gear set to harden the surface of the shaped teeth tended todistort the shape of the face gear set during the hardening operation.

A previous method of manufacture of face gears was developed by FellowsCorporation. The method uses a gear shaper apparatus, and the finishedproduct is useful for low power applications.

The Fellows Corporation method employs a metal cutting process forshaping the gear teeth of the face gear. This process can only beapplied to materials with suitable hardness and metal cuttingcharacteristics. If the material is too hard, the shaper tool will notcut effectively. This shaping process can only be used effectively forfinish cutting face gear teeth from metals suitable for low powerapplications. This process does not give the accuracy and surface finishrequired for higher power applications.

The applicants have previously developed a novel method and apparatusfor manufacturing face gear sets suitable for high power transmissionapplications, which method and method and apparatus are described inU.S. Pat. No. 6,390,894. That document is herein incorporated, in itsentirety, by reference.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a precision grinding apparatus forgrinding face gears having a gear table portion controllably driven forrotation about a central axis, and also being movable in a verticalplane along an axis in a controlled manner. The apparatus furtherincludes a case hardened face gear mounted on the gear table portion. Agrinding wheel mounted on the apparatus has controlled driven rotationabout a central axis C, and is provided with a grinding surface ofpredetermined shape. The grinding wheel is movable in a controlledmanner toward and away from the gear along a feed axis V, the grindingwheel being movable in a controlled manner in a tangential directionwith respect to the gear and orthogonal to the feed axis V along atangential feed axis TF wherein the motion of the grinding wheel in theC, V and TF axes, and movement of the gear in B and W axes, iscontrolled by a central control means.

In an alternate embodiment of the present invention, the apparatusfurther includes a feed mechanism for generating teeth on a face gear,said feed mechanism adapted to move said face gear in a compositevertical and horizontal direction such that said face gear traverses theentire width of the tooth face of said face gear.

In yet another embodiment, the present invention provides a grindingapparatus for a tapered pinion gear having a base with a grindingportion mounted thereon for generating teeth in a gear by abrasion, agear driving portion mounted on said base in juxtaposition to andcooperating with the grinding portion, and a case hardened taperedpinion gear having preformed teeth of a predetermined size andconfiguration mounted on the gear driving portion. In this embodiment,the gear driving portion has the capability of rotating the pinion gearin a manner controlled by a first CNC control portion in a central axisdesignated B1, and also has the capability of moving said pinion gear upand down in a vertical axis designated W in a manner controlled by asecond CNC control portion. The grinding portion includes a grindingwheel having a grinding surface thereon in which a worm of predeterminedconfiguration is generated, and is rotatably driven and controlled by athird CNC control portion to control the rotation of the grinding wheelin its central axis designated C. The grinding wheel also includes afourth CNC control portion to control the motion of the grinding wheeltoward and away from said pinion gear along a V axis, and a fifth CNCcontrol portion to control the motion of the grinding wheel in atangential direction with respect to the pinion gear and orthogonal tosaid V axis along a TF axis. The CNC control portions cooperate togetherto mesh said worm with said teeth of said pinion gear to form teeth insaid gear in a continuous grinding operation.

Any of the described embodiments of the present invention may furtherinclude a high-pressure temperature-controlled coolant system to preventburning of the gear teeth during grinding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a prior art spur gear cutting machine.

FIG. 2 is a partial view of a prior art blank grinding wheel (before thewheel is shaped).

FIG. 3 is a partial view of a spur gear grinding wheel of the prior artshowing the dressing tool used to provide a cutting profile.

FIG. 4 is a perspective view of a face gear and a mating pinion gear.

FIG. 5 is a sectional view of a mating pinion and face gear.

FIG. 6 is a sectional view of a prior art face gear shaping apparatus.

FIG. 7 is an elevational view of a grinding apparatus of the presentinvention adapted for grinding teeth on regular, concave, and convexface gears.

FIG. 8 illustrates exemplary regular, concave, and convex face gears.

FIG. 9 is a perspective view of a complete grinding machine for grindingteeth on a convex face gear and constructed in accordance with theteachings of the present invention.

FIG. 10 is a plan view of the grinding wheel of the present inventionshowing associated dresser apparatus motion.

FIG. 11 is a plan view of a grinding machine constructed in accordancewith the teachings of the present invention.

FIG. 12 is a spatial representation of the three major components of aface gear machine constructed in accordance with the teachings of thepresent invention, to more clearly illustrate the various componentaxes.

FIG. 13 is a spatial representation of the three major components of aface gear machine constructed in accordance with the teachings of thepresent invention and adapted for producing teeth on a pinion gear.

FIG. 14 is a perspective view of a face gear grinding apparatus adaptedfor producing teeth on a pinion gear.

FIG. 15 is an elevational view of a grinding wheel showing a typicalface gear configuration used in this invention.

FIG. 16 is an end view of the machine of FIG. 9.

FIG. 17 is an elevational view of the machine of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the drawings, wherein like numerals represent like parts,the numeral 10 represents generally a prior art spur gear grindingapparatus. A machine 12 (partially shown) is provided with a moveablecarrier 14 that is capable of executing rectilinear motion, as indicatedby a double arrow 16. Carrier 14 is provided with a gear driving head18, which is connected to lead shaft 20. The end of shaft 20 remote fromdriving head 18 is centered in tailstock 22 in order to stabilize shaft20. A spur gear 24 is mounted on shaft 20 so as to be controllablyrotated by driving head 18.

A spur gear grinding wheel 26 is shown engaging the peripheral surfaceof spur gear 24. Grinding wheel 26 takes the same form as grinding wheel36, shown in FIG. 3, and must be capable of movement toward and awayfrom gear 24 as indicated by double arrow 28. The rotation of thegrinding wheel is coordinated with the rotation of the spur gear.

To produce a ground spur gear, the grinding wheel 26 is advanced towardgear 24 while gear 24 is synchronously rotated to be in step with the“worm” profile at grinding wheel 26, until grinding wheel 26 hasadvanced to the desired depth into a selected area of the spur gear. Thespur gear is now gradually moved in an axial direction to permitgrinding wheel 26 to complete the grinding along the tooth length of thegear. This process is repeated for increased material removal untiltooth size and profile are achieved.

FIG. 2 shows a grinding wheel 30 of the prior art before being dressedto have a grinding profile.

FIG. 3 shows a grinding wheel 36 that contains a worm profile 38 (usedfor grinding spur gear teeth as previously described), which profile isformed by dressing tool 40, which carries a specially shaped dressingdisc 42 to provide the worm profile. The dressing tool 40 is movedacross the surface of the grinding wheel 36 as grinding wheel 36rotates. Disc 42 is advanced into the surface of wheel 36 until thedesired tooth form is achieved. The shape of profile 38 on the surfaceof wheel 36 is formed by the shape of the profile of grinding disc 42(i.e. the axis of rotation of disc 42 is usually parallel to the axis ofrotation of wheel 36).

FIG. 4 shows an illustration of a regular face gear 50 and a meshingpiston 52. The teeth 54 on face gear 50 extend in a radial direction;the teeth 56 on pinion 52 are parallel to the axis of rotation of pinion52.

FIG. 5 shows the face gear 50 and pinion in section. The teeth 54 and 56are shown in a meshed condition.

FIG. 6 is an illustration of a prior art method of shaping the teeth onface gear 50 by shaper cutter 60. The shaper cutter 60 is reciprocatedin an axial direction (as shown by arrows 62) while it and the face gear50 and the shaper cutter 60 are constantly moving in a simulated meshingengagement, until the desired tooth form has been generated.

FIG. 7 depicts a face gear work head 68 and face gear grinding head 100constructed in accordance with the teachings of the present invention.The embodiment shown in FIG. 7 is used for grinding the teeth of eitherregular, convex, or concave shaped face gears. In the illustration, aconvex face gear 70 is shown mounted on a controllable rotating table 72so as to rotate about axis 74. Rotating table 72 is directly mounted onCNC drive motor 80. Motor 80 serves to drive rotating table 72 and ismounted directly on base 76. Face gear work head 68 is able to swivelabout swivel axis 78. The degree of swivel of face gear work head 68 isclosely controlled by swivel selector 108, shown in FIG. 9. The entirerotating face gear head 68 is preferably capable of executing controlledmotion in a vertical direction during a tooth grinding operation, asshown by arrow 90. CNC control permits controlled motion in the verticalaxis. In the illustration shown, the gear axis of rotation is maintainedin a horizontal orientation during grinding.

Grinding head 100 has a grinding wheel 102 rotatably mounted thereon.Grinding head 100 is precisely located with respect to face gear workhead 68 and grinding wheel 102. The whole grinding head 100 must becapable of executing controlled motion in a horizontal direction duringa tooth grinding operation as shown by arrow 210. CNC control permitscontrolled motion in the horizontal axis.

Grinding wheel 102 is provided with a special worm profile 268 (see, forexample, FIGS. 10 and 15), and the grinding operation is carried out byadvancing grinding wheel 102 toward face gear 70 so that grinding wheelprofile 268 and the face gear mesh precisely (i.e. the worm of grindingwheel 102 has a profile that meshes with the teeth of face gear 70). Thefeed mechanism for generating the teeth on face gear 70 slowly movesface gear 70 in a composite vertical and horizontal direction until thegrinding wheel has traversed the entire width of tooth face 71 of facegear 70. Grinding wheel 102 is gradually advanced into the surface oftooth face 71 of face gear 70 with each succeeding pass, until thedesired tooth profile 268 is produced.

FIG. 8 shows examples of configurations of face gears that the presentinvention is capable of grinding. Regular face gear 50, convex face gear70, and concave face gear 106 can all be ground using the teachings ofthe present invention. The criteria used for determining the face geardescription include the angle measurement between the gear tooth face 71and the gear axis of rotation 82. The present invention can also beadapted to grind a pinion gear, detailed below, not shown in thisfigure.

FIG. 9 depicts a full grinding machine 200 constructed in accordancewith the teachings of the present invention. A base 202 is provided topermit face gear work head 68 to be mounted thereon in a predeterminedfashion. This apparatus drives rotating table 72 on which face gear 70is mounted in a controlled manner about its axis (designated axis “B”).Rotating table 72 is directly mounted on CNC drive motor 80. Motor 80serves to drive rotating table 72 and is directly mounted on base 76.Base 76 is mounted on work table 214, which allows face gear work head68 to also swivel about its mounting on worktable 214. This permits theface gear to have a manually adjustable angular swivel settingdesignated as the “WTS” axis. Worktable 214 is constrained to permit itto move in a vertical plane along rails 216 by drive motor 222. Thisvertical axis is designated as the “W” axis.

Grinding head 100, on which grinding wheel 102 is mounted, is mounted onbase 202 in such a manner that grinding wheel 102 may be moved towardand away from face gear work head 68, and grinding wheel 102 may movetangentially to work head 68 as well. Grinding head 100 is permitted tomove along rails 259 to produce the motion of the carriage 254 towardand away from face gear work head 68. This is a feed axis, which isdesignated as the “V” axis. Carriage 254 is also mounted on rail 252 toproduce the motion of grinding wheel 102 in a tangential direction withrespect to face gear 70. This axis is designated as the “TF” axis.Grinding table 258 is capable of pivoting carriage 254 about pivot 260.This is the grinding wheel pivot axis and is designated as the “WT”axis. Grinding wheel 102 rotates about an axis designated as axis “C”and is driven by motor 262, which is integrally mounted on carriage 254.Grinding wheel 102 has a predetermined profile inscribed on its surfaceas shown in FIG. 10. Other views of the grinding machine of FIG. 9 areprovided in FIGS. 16 and 17.

During the initial set up of machine 200, axes “TF” and “WT” are set andlocked with respect to the tooth configuration already existing on facegear 70. (Face gear 70 has already undergone tooth shaping and surfacehardening operations before being mounted in machine 200). During theinitial approach of grinding wheel 102 to face gear 70, motor 262 isrotating grinding wheel 102 about axis “C” and motor 80 is rotating facegear 70 about axis B. The rotation of axis “C” & “B” are in a prescribedsynchronized manner. Carriage 254 is fed along the “V” axis to carrygrinding wheel 102 toward face gear 70 until the desired grindingposition is reached. During grinding, face gear table 214 undergoescontrolled movement along the feed axis “W” and grinding head 100undergoes controlled movement along the feed axis “V” until the grindingwheel has moved sufficiently so that the entire tooth face 71 of facegear 70 has been traversed by grinding wheel 102. Grinding wheel 102 isthen moved slightly toward table 214 and the grinding operation isrepeated until the desired depth of the tooth form and shape isgenerated.

A rotary diamond dressing tool assembly 264 is also mounted on grindingtable 258, along rail 256. Assembly 264 includes a rotary device 266,which rotates a diamond impregnated disc 280 (see FIG. 10). Disc 280 isused to generate (by abrasion) a prescribed form in grinding wheel 102.Device 266 is adjustable in height and angle on and about post 270, onwhich device 266 is mounted. The entire dresser assembly 264 is mountedon table 258 so as to be capable of controlled motion in three axes. Afirst axis of motion allows the dresser assembly mounted on feed table274 to move backwards and forwards along rails 272 away from and towardsgrinding wheel 102. This axis is designated as the “Y” axis.

Movement of dressing tool assembly 264 along rails 256 in a translatoryfashion (parallel to the axis of grinding wheel 102) is designated asthe “X” axis. Movement of dresser wheel 280 about post 270 in an angularfashion will define the angular axis “A”. The grinding wheel profiledemands that the move-ment of feed table assembly 274 for dresserassembly 264 be synchronized with the rotation of grinding wheel 102such that disc 280 of dresser assembly 264 properly meshes the profileof grinding wheel 102.

The grinding operation of the partially completed and surface hardenedface gear 70 is as follows:

Rotating table 72 is manually set to a predetermined tilt (WTT) andswivel (WTS) settings and these positions are locked. The partiallyfinished gear is mounted on rotating table 72 so as to have apredetermined angular position on axis “B”. Grinding wheel carriage 254is then set at the appropriate angle on the pivot axis WT and locked.Carriage 254 is moved along rail 252 until grinding wheel 102 is set ata predetermined position on the “TF” axis with respect to face gear 70.

The rotating grinding wheel 102 is now moved along the “V” “feed” axisto move toward the partially finished rotating face gear 70 in ahorizontal direction. Next, rotating face gear 70 is moved along the “W”“feed” axis towards the engagement point with the rotating grindingwheel in a vertical direction. These linear axes can be movedindependently or simultaneously under CNC control to achieve the initialface gear grinding position.

To perform the grinding of face gear 70, and to permit the grindingwheel 102 to traverse the entire width of tooth face 71 of gear 70, worktable 214 is now moved vertically along rails 216. Carriage 254 is movedhorizontally along rails 259 under CNC control in a composite manner.The combined CNC motion of the “V” & “W” feed axis enables the face gearmanufacturing apparatus to grind various face gear configurations(concave to convex), as will be apparent to those of skill in the artupon reading this disclosure. This process is repeated in a series ofgrinding passes until the desired size and tooth configuration isgenerated in face gear 70.

Periodically, during the grinding operation, the profile of the grindingwheel 102 must be restored. When this is necessary, grinding wheel 102is retracted from face gear 70 and dresser assembly 264 is brought intoposition on rails 272 and 256 to engage grinding wheel 102 and torestore the profile on wheel 102 to its original profile. Grinding disc280 is engaged with grinding wheel 102 in accordance with CNC control tomove in a controlled manner to restore the profile 268 to wheel 102 toits required dimensional shape.

FIG. 14 shows the apparatus of FIG. 9 modified to permit the finishgrinding of a pinion gear 300. Pinion 300, in this instance, is atapered spur gear pinion. Grinding wheel 302 now carries a significantlydifferent profile from the profile inscribed in the surface of grindingwheel 102 for face gear grinding. The profile inscribed on the surfaceof wheel 302 is similar to that shown in FIG. 3.

The face gear work head 68 of FIG. 9 has been replaced with work table304, which supports and rotates pinion 300 during grinding.

Tapered pinion 300 rotates about an axis designated as “B1” in anangular motion synchronized with grinding wheel 302. The worktableassembly 304 is capable of vertical translatory motion along rails 216,designated the “W” axis as previously described with respect to FIG. 9.The motion of grinding wheel 302 along the “V” axis is CNC controlled,as is the movement of pinion 300 along the “W’ axis. It will be obviousto those skilled in the art that the motion of grinding wheel 302 in the“V” axis must be carefully coordinated with the motion of table 304along rails 216 in order to produce tapered spur gear pinion 300.

The dresser apparatus for grinding wheel 302 is required as previously,but is ormitted from FIG. 14 for reasons of clarity.

It is further contemplated that any of the face gear grinding devices ofthe present invention may include a high-pressure temperature-controlledcoolant system to prevent burning of the gear teeth being ground.

The axes defined herein are as follows:

AXIS DEFINITION CONTROL C Grinding Wheel 102 (302 Rotation CNC VGrinding Wheel 102 (203) in Feed CNC WT Grinding Wheel 102 (302) TiltManual TF Grinding Wheel 102 (302) Tangential CNC or Feed Manual BRotating Table 72 Rotation (Face Gears) CNC B1 Driving head 318 Rotation(Tapered Spur CNC Gear Pinion) W Work Table 214 Axial Feed CNC WTS WorkHead 212 (69, 304) Swivel Manual A Dresser Tool 264 Rotary Feed CNC XDresser Tool 264 Cross Feed CNC Y Dresser Tool 264 In Feed CNC DHDresser Tool 264 Height Manual DT Dresser Tool 264 Tilt Manual

Basic Operation of the Face Gear Grinding Machine

FIG. 11 provides a plan view of a face gear grinding machine constructedin accordance with the teachings of the present invention. Machine 200utilizes a CNC system that enables the axes under its control to bemoved in a predetermined manner via a set of instructions in a program.Numerous programs will be created to control the dressing cycle and geargrinding cycle of machine 200 for different configurations of gears. TheCNC control enables the axes of motion to be continually synchronizedeven when switching between the dressing and grinding cycles.

Manual Settings

The work table 212 swivel “WTS” is commonly set in the vertical positionand locked for the gears described herein. This feature is incorporatedfor helical gear form requirements. Grinding wheel 102 tilt “WT” is setfor lead angle compensation. Grinding wheel tangential feed “TF”positions the wheel with respect to the central axis of the gear in ahorizontal plane. This feature, when CNC controlled, is incorporated forhelical gear form requirements. Dresser rotary device 266 tilt is setfor angular clearance “DT” and diamond disc 280 grinding wheel 102centerline height “DH”.

Grinding Wheel Dressings CNC Controlled

CNC programs stored in the memory of the CNC control are selected tocontrol this process. These programs command the motion of dresser axesX, Y, A, and grinding wheel 102 axis C in a prescribed manner togenerate the required form on the grinding wheel. These programs controlthe speed and direction of rotation of grinding wheel 102 with respectto the speed and direction of motion of dresser assembly 264, axis X, Yand A.

Via the CNC and the selected program, the speed of rotation of grindingwheel 102 (axis C) relative to the speed of rotation of gear 70 (axis B)being ground is controlled. This relationship is controlled via anelectronic gearbox, which is a feature of the CNC. It is an importantfeature as the grinding process simulates the meshing of a worm gearwhich is the grinding wheel 102 with a face gear such as 70, which isthe gear being finish ground. Also via the program and CNC, thefollowing functions are also controlled:

Depth of Cut (axis V)—infeed of grinding wheel 102 to workpiece (facegear 70);

Vertical feed of workpiece across grinding wheel 102 (axis W);

Tangential Feed (TF)—positioning of grinding wheel 102 to workpiece(face gear 70);

Dresser diamond disc 280 speed;

Control of dresser motion X, Y and A axis for initial and periodicre-dressing of the grinding wheel 102;

Dimensional offsets and adjustments; and

Coolant on/off, and machine lubrication.

Examples of the composition of the basic material for gear 70 that maybe used successfully to practice the present invention is:

(a) SAE 9310 having components

Iron—94.765%

Nickel—3.25%

Chromium—1.20%

Manganese—0.55%

Molybdenum—0.11%

Carbon—0.10%

Silicon—0.045% max; or

(b) PYROWEAR ALLOY 53 having the following components:

Iron—90.2%

Molybdenum—3.25%

Copper—2.00%

Nickel—2.00%

Chromium—1.00%

Silicon—1.00%

Carbon—0.1%

Vanadium—0.1%

The foregoing description of the embodiments of the invention has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or to limit the invention to the precise formdisclosed. The description was selected to best explain the principlesof the invention and practical application of these principles in orderto enable others skilled in the art to best utilize the invention invarious embodiments and with such modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention not be limited by the specification, but be defined by theclaims as set forth below.

1. A precision grinding apparatus for grinding face gears comprising: asuitable gear table portion being controllably driven for rotation abouta central axis, said gear table portion also being movable in a verticalplane V along an axis in a controlled manner; a case hardened facemounted on said gear table portion, said face gear having a series ofgear teeth formed therein; and a grinding wheel mounted on saidapparatus, said grinding wheel having controlled driven rotation about acentral axis C, said grinding wheel being provided with a grindingsurface of predetermined shape, said grinding wheel being movable in acontrolled manner toward and away from said gear along a feed axis V,said grinding wheel being movable in a controlled manner toward in atangential direction with respect to said gear and orthogonal to saidfeed axis V along a tangential feed axis TF, wherein the motion of saidgrinding wheel in said C, V and TF axes, and movement of said gear in Band W axes, is controlled by a central control means.
 2. A precisiongrinding apparatus as claimed in claim 1 wherein a dressing apparatus ismounted on said apparatus in a predetermined relationship with saidgrinding wheel, said dressing apparatus comprising: a driven grindingdisc of a second predetermined shape for controlled motion toward andaway from said grinding surface of said grinding wheel along a Y axis,said disc being mounted on said apparatus for movement along an axis Xsubstantially parallel to said C axis of said grinding wheel, andwherein said X axis is orthogonal to said Y axis, said disc also beingcapable of angular movement about a central dressing axis A, and whereinsaid movement in said X, Y and A axis is coordinated by and under thecontrol of said central control means to create and restore saidgrinding surface of said grinding wheel to said predetermined shape. 3.The grinding apparatus of claim 1 wherein said grinding surface isshaped in the form of a worm for meshing with an grinding the gear teethexisting on said gear to a predetermined finished shape.
 4. The grindingapparatus of claim 1 wherein said grinding wheel is movable in adirection along an axis TF tangential to said gear and orthogonal tosaid V axis, and said grinding wheel is capable of being tilted about atilt axis WT.
 5. The grinding apparatus of claim 4 wherein a dressingmeans is provided for creating and restoring the profile of said worm ofsaid grinding wheel.
 6. The grinding apparatus of claim 1 wherein saidgrinding wheel is movable along an axis TF tangential to said gear, andsaid grinding wheel is tiltable about a pivot axis WT.
 7. The grindingapparatus of claim 1 further comprising a feed mechanism for generatingteeth on a face gear, said feed mechanism adapted to move said face gearin a composite vertical and horizontal direction such that said facegear traverses the entire width of the tooth face of said face gear. 8.The grinding apparatus of claim 1 wherein said central control means isa computer numerical control (CNC).
 9. The grinding apparatus of claim 1wherein said apparatus is adapted for producing teeth of a gear having ashape selected from the group consisting of regular, concave and convex.10. The grinding apparatus of claim 1 further comprising a coolantsystem.
 11. The grinding apparatus of claim 10 wherein said coolantsystem is a high-pressure temperature-controlled coolant system adaptedto prevent burning of said teeth during grinding.
 12. A precisiongrinding apparatus for a tapered pinion gear comprising: a base having agrinding portion mounted thereon for generating teeth in a gear byabrasion; a gear driving means portion mounted on said base injuxtaposition to and cooperating with said grinding portion; and a casehardened tapered pinion gear having preformed teeth of a predeterminedsize and configuration mounted on said gear driving portion, said geardriving portion having the capability of rotating said pinion gear in amanner controlled by a first CNC control portion in a central axisdesignated B 1, said gear driving portion also being provided with thecapability of moving said pinion gear up and down in a vertical axisdesignated W in a manner controlled by a second CNC control portion,said grinding portion comprising a grinding wheel having a grindingsurface thereon in which a worm of predetermined configuration isgenerated therein, said grinding wheel being rotatably driven andcontrolled by a third CNC control portion to control the rotation ofsaid grinding wheel in its central axis designated C, said grindingwheel further having a fourth CNC control portion operably associatedtherewith to control the motion of said grinding wheel toward and awayfrom said pinion gear along a V axis, and said grinding wheel furtherhaving a fifth CNC control portion operably associated therewith tocontrol the motion of said grinding wheel in a tangential direction withrespect to said pinion gear and orthogonal to said V axis along a TFaxis, wherein said CNC control portions cooperate together to mesh saidworm with said teeth of said pinion gear to form teeth in said gear in acontinuous grinding operation.
 13. The grinding apparatus of claim 12wherein said grinding wheel portion is movable along an axis tangentialto said gear designated TF, and said grinding wheel portion is tiltableabout a pivot axis designated WT.
 14. The grinding apparatus of claim 13further comprising a grinding wheel dressing portion mounted incooperating relationship with said grinding portion to engage saidgrinding surface in a manner controlled by three additional CNC controlportions to create said worm and restore said worm to its predeterminedconfiguration when a predetermined amount of distortion is present insaid worm.
 15. The grinding apparatus of claim 14 wherein said threeadditional CNC control portions include: a sixth CNC control portion tooperably associated with said dressing portion to control the motion ofsaid dressing portion toward and away from said grinding surface alongan axis designated Y; a seventh CNC control portion operably associatedwith said dressing portion to control the motion of said dressingportion along an axis substantially parallel to said C axis, designatedX; and an eighth CNC control portion operably associated with saiddressing portion to control angular motion of said dressing portionabout a pivot axis designated as A.
 16. The grinding apparatus of claim14 wherein said dressing portion comprises a disc having a predeterminedshape for engaging said surface of said grinding wheel to restore saidworm configuration by abrasion.
 17. The grinding apparatus of any ofclaims 12 through 16 further comprising a coolant system.
 18. Thegrinding apparatus of claim 17 wherein said coolant system is ahigh-pressure temperature-sensitive coolant system adapted to preventburning of said teeth during grinding.